inflating circles patch…perhaps a bit slow

So I actually have a chance to play with gl.sketch, so I cooked up this
nifty op-arty patch to draw "inflating circles", but I’m sure there’s a
more elegant and speedier way to do it. This is the result of
extremely linear thinking…..

Any suggestions, patched or otherwise? Would a js version of this be
more efficient?

thanks,

Peter

(requires the rndlist abstraction, and the "_" object, or an
abstraction called "_" that just has "prepend set" in it.)